This invention relates to systems for mounting movable thrust nozzles to rocket cases; more specifically, it relates to frictionless systems wherein the nozzle is mounted to the rocket case by a fluid-filled bearing.
Such systems are known in the art; but the known systems have certain disadvantages that are overcome by the present invention.
U.S. Pat. No. 3,446,437, cited above, describes a rocket nozzle supported relative to a rocket case by an annular, fluid-filled bladder divided into cells by partitions. Diametrically opposite cells are connected together by tubes and hydraulic actuators are interposed in the tubes, whereby fluid may be removed from one cell and pumped into the other to move the nozzle and steer the rocket. Disadvantages of this system are that the annulus of fluid imparts considerable weight of inert parts to the rocket, the entire annulus must be made in one piece, and considerable stress is impressed on the partitions of the bladder when fluid pressure in adjacent cells is made unequal.
U.S. Pat. No. 3,698,192 "Universal Joint Employing a Fluid Bearing for a Movable Nozzle" by C. A. LeFebvre and U.S. Pat. No. 3,727,408 "Universal Joint Employing a Fluid Bearing" by S. A. Martin both show annular volumes of fluid, as applied to rockets; and, hence, they impart the same weight penalty as the invention described in Patent No. 3,446,437.
In addition to the weight problem an annular bladder is difficult to manufacture, and the cost increases dramatically with the size of the bladder. Also, a defect in any part thereof necessitates discarding the entire bladder.